PV Installations & Errors

PV Installations & Errors
Prevent Errors upfront
Andreas Iliou / Suntech

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Photovoltaic Systems
Energy Audits
Protection

Maximum Power Point Tracking (MPPT)
Weak light – Shading

Microcracks Production,
during Transport and Installation

Energy Audits
Protection

Backfeed Current
Leakage Current

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01

Energy Audits
Protection

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Reason for less power output
 Power Plant with less kWh/kWp compared
with nearby installations
 Planning layout / Optimization
 Mismatch losses due to wrong inverter / module
combination (high losses ) resize cable diameters
 Strings not correctly installed,single modules not
Connected polarity wise – connectors without contact
 Mismatch losses can be changed regards inverter
e.g Multistring inverter agains 1 Tracker
 Shading not upfront recognised, restring or
reinstallation of different invertertype

Cleaning of inverters regularly (heat transfer /cooling!)
to hot surface temperature at cooling and/or AC side
testing procedureI-V curve testing

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 Power Plant with less kWh/kWp compared
with nearby installations
 Planninglayout/Optimizing
 Distance of inverters to close by
 Inverter cools down from right to left therefore
heating up uneccessarily second and third inverter
 Losses due to planning and/ or installation
mistakes accumulates up to 250 W losses
 Systems runs without ( Datalogger )
no stringcontrol,
 Inverter covered and overheats , built in a small room
no cooling possible,
cuts off frequently without problems
Iso faults, shortcuts etc.



Inverters must be installed according manual

Source Mastervolt
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Alternative Solution: Board can be used to split incoming Air

All Rights Reserved Source Mastervolt

Different topologies involved

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Shaded or already to less modules planned


Optimising Power output
Optimum East- / Westconfiguration: 2:1 = 2 Strings right and 1 String left
3:1 = 3 Strings right and 1 String left


Tests to determine less power output

 Check of all AC outlets

 Check of all earth wires

 Polaritytest of each string

 Testing of all Stringvoltages

 Measurements of shortcut current

 Isotest of all DC strings

 Performance test and visual inspection
of all components


Tests to determine less power output
Check poweroutput with the Voltage AC grid


Testing procedure – less power output

• Visual Inspection Check of all AC outlets

• Isolationtest

• Check of all deactivation figures

• Cable size and resistance check

• Values should be underneath <1 Ohm

• Feed in AC checked with AC site



• Are modules covered with grease or dust ->
please check

• Contacts faulty , check each single string

• Bushes or trees grown up

Is it possible to increase or still decrease MPPT
from the inverter or are to less modules connected
when Shading occures with more than 1 single
module
Involved.
Temperature zone concept been used
Are more systems already been built in the
neighbourhood


No power output during daytime

Meter doesn t turn
Still to dark outside, check later on again

 Circuit breaker turned down ?
 Switch defect ?
 Lightning protection device faulty? ->current flowing
 During winter everything worked fine , ½ year later
extremely poor output achieved

always during high peak and high temp->low output
 Power failure Main Grid
 Iso fault with no reason, check contacts involved
 Single test of each string
 Data locked at inverter -> please check
 Failure in AC Supply , please check with earth loop tester


Less power output due to stray currents


Less power output
cause is stray , and ground currents

PE+Neutral bound together- lot s of stray currents ,more losses


Less power output
cause is stray , and ground currents

PE+Neutral seperate - NO currents ,less losses involved


PV Installations & Errors

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PV Installations & Errors